Method of treating wood for the rapid maturation of whiskey and other alcoholic liquors and wines



Patented May3l, 1938 2,1

UNITED STATES PATENT OFFICE- RAPID MATURATION OF WHISKEY AND ALCOHOLIC LIQUORS AND WI NES Ernst 'r. Krebs and Ernst 'r. Krebs, 'Jr., San Francisco, Calif.

No Drawing. Application July 14, 19a.

Serial No. 153,674

6 Claims. (Cl. 99-48) This invention is a modification and improveordinary writing paper and then toasted to alight ment over our former patent entitled Method of golden brown color in a revolving or other suittreating oakwood for the aging of spiritous able toaster. To each bulk gallon of toasted chip liquors, No. 2,070,794, issued February 16, 1937. shavings is added about 500 c. c. of water, which The object of the present invention is to prois well mixed with'the chip shavings until they vide a method whereby the so-called aging .become uniformly-moistened. The next day about changes occur more rapidly, more tannoid reducthree ounces of the mother enzyme solution contion is insured, and higher acid development and taining the ether, as previously specified, is added greater economy is obtained. and thoroughly mixed through 'the moistened The method is divided into four steps: first, the shavings, and after about twelve hours the ves- 10 preparation of the enzymes; second, the prepasel containing the shavings is kept well covered ration of the wood; third, the treatment of the until the treatment is completed. .In the treatwine or liquor with the wood; and fourth; the ment of'the shavings with the mother enzyme final marrying or stabilization of the liquor. solution containing ether, from fifteen to thirty In describing the first step of the process, 'todays is required. I wit the preparation of the enzymes, an example The shavings shouldbe frequently tested for will be given using the kernels of Prunus'armeacid development, beginning about the tenth day, niaca for the extraction of the enzymes.- Howand when the acid development in the shavings ever, the kernels of any other of the Prunus' turns blue litmus paper tov a distinctpink color, family may be used, or many other 'seedssuch as a small sample'of the shavings should be digested mustard, rape, hemp, etc., may be used for this in one hundred proof alcohol for an hour or two, process with more or less-satisfactory results. In and this solution should be tested by adding a fact, the enzymes which are an emulsin complex drop or two of a one per cent solution of ferric maybe obtained from other sources such as yeast, chlorideto about 4 c. c. of the alcoholic extract. 'crytogamic growths, fungi, algae, certain bac-' When the test shows an amber or olive green teria, etc. color, the shavings are ready to receive the raw One pound of the kernels of the seed of Prunus whiskey or other liquor or wine'to. be aged.

' armem'aca, fresh or partly germinated, of the In the case of whiskey, about three to six times current year is ground in a grinding machine (depending upon the character of the wood) the and thenplaced in a ball mill with 1000 c. c. of quantity of whiskey to bulk shavings is added water and ground for several hours. As the and allowed to macerate one hour. It is then emulsion thickens more water is added until drawn off and the proof is taken and enough about 2000 c. e. have been added. When a fine, water or newwhiskey is added tobring it to one almost impalpable emulsion is produced, remove hundred and two proof. It is now poured back the emulsion from the ball mill and add about upon the shavings and allowed to macerate for 400 c. c. of ether. Now agitate vigorously for at several hours and then-percolated off and placed least ten minutes. Then pour in a percolator and in glass or charred oak containers for at least allow .to remain for twelve hours more or less. thirtydays to undergo the change which whiskey When the. aqueous layer separates to the' bottom manufacturers call marrying, which is a stabilizaof the percolator, it is drawn oif and placed in a tion process, no doubt, of ionization and further 40 tightly stoppered bottle for use. This is the esterification. In theaging of Scotch whiskey,

mother solution containing the enzymes sought more or less untoasted chip shavings should be and aboutv 8% ether. This solution. should be added to the treated toasted chip shavings.

kept in a cool place and used within seventy-two It appears that emulsin itself is not the agent hours. a a which is directly responsible for thechange in The second operation of the process concerns. the chemical structure of'the tanninsand tannic the preparation of the wood. The wood of compounds of "the wood. The emulsin complex Quercus albd. will be taken as an example for the stimulates a profuse cryptogamic growth, which preparation of the wood since whiskey and other growth produces an emulsin complex rich in tanliquors and wines are usually aged in containers nase, and it is apparently this emulsin complex made of this wood, although the wood of which {changes the tannins and tannicv com- Glycyrrhiza glabra, althea, et'c., will produce pounds.

practically the same results. The well seasoned For wine, the process of treating the chip shav-" dry wood of Quercus alba. is comminuted prefings is precisely the same. The amount of wine erably as chip shavings about the thickness of to be added to the treated shavings and length of the first step of treating the shavings, the tannins again become hydrated, which tannoid is apparently an intermediate tannoid body between gallic and ellagic acid, giving a blue reaction with ferric salts. When these are later acted upon by the emulsin complex rich in'tannase secreted by the cryptogamic growth, they are apparently oxidized to ellagic acid, which again gives a green coloration with ferric salts. The ether contained in the mother liquid containing the enzymes com bines with the hydrated and partly broken down tannins, losing its oxygen and forming an ethyl compound with these tannins, any excess of ether forming acetic and allied acetic acids.

The enzymes represented by the emulsin complex stimulates a profuse cryptogamic growth from the shavings, which growth is rich in aminosuccinamide. The cryptogamic growth secretes an emulsin complex which is rich in tannase. This complex, mainly through its tannase constituent, further breaks down the tannoid bodies, forming, apparently, mainly ellagic acid which gives an olive green color with ferric salts. The aminosuccinamide furnishes oxygen to the reaction and splits up into succinic and succinamic acids and amino compounds with products of the tannin.

When the new whiskey containing ethyl and other alcohols is added to the treated shavings and is allowed to macerate for several hours, all the changed products of the wood which are soluble in a hydro-alcoholic. solution dissolve, leaving practically nothing behind but the cellulose, and it is for this reason that only a few hours are required for the maceration of the hydro-alcoholic solution in the treated wood. The whiskey is now placed in suitable containers, such as charred oak barrels, glassware, or the like, as it needs no further treatment with the oakwood.

The reaction which takes place between the products leached from the wood, and the whiskey, are as follows: The aminosuccinamide breaks down into succinic-and succinamic acids, and the amino constituent forms compounds 'with the broken down tannoid bodies (mainly querco-glycyrrhizic acid) this furnishes the oxidation required to bring about aldehydation and acetylization. Esterification follows slowly as a matterof course. At the end of thirty days, the whiskey can be drawn off from the slight sediment and bottled, and is ready for use, the maturity of the whiskey being equivalent to a sixor eight year old product aged in the customary way in charred oak barrels.

This method produces the same biological- (cryptogamic growth). and chemical phenomena which occur in the staves of the charred oak barrel containing whiskey with the advantages that the so-called aging changes occur more rapidly, and more tannoid reduction, higher acid development and greater economy is obtained. The principal advantage is due to better tannoid reduction and greater ethyl esterification of the tannoid acids due to introducing the ethyl radical in the form of ether and apparently forming tannic, gallic and ellagic aldehydes or principally the latter which otherwise form slowly.

Having thus described our invention, what we claim and desire to secure by Letters Patent is:

1. A method of treating oak wood to stimulate a profuse cryptogamic growth in the wood, which growth is rich in aminosuccinarnids and an emulsin complex rich in tannase, the steps which consist in reducing the wood to comminuted form, toasting it to dehydrate the tannin contained, and moistening the comminuted toasted wood with a solution containing an emulsin complex and ether and maintaining the wood in the moistened condition until a maximum cryptogamic growth and the resultant secretion of emulsin complex rich in tannaseis obtained.

2. A method of treating oak wood to stimulate a profuse cryptogamic growth in the wood, which growth is rich in aminosuccinamids and an emulsin complex rich in tannase, the steps which consist in reducing the wood to comminuted form, toasting it to dehydrate the tannin contained, and moistening the comminuted toasted wood with a solution containing an emulsin complex and ether which will produce esterification and maintaining the wood in the moistened condition until a maximum cryptogamic growth and a secretion of emulsin complex rich in tannase is obtained.

3. A method of treating oak wood to stimulate a profuse cryptogamic growth in the wood, which growth is rich in aminosuccinamids and an emulsin complex rich in tannase, the steps which consist in reducing the wood to comminuted form,-

toasting it to dehydrate the tannin contained, moistening the comminuted toasted wood with a solution containing an emulsin complex and ether, maintaining the wood in the moistened condition until a maximum cryptogamic growth is obtained andv a secretion of emulsin complex rich in tannase is formed, and leaching the treated wood with the liquor to be aged until the changed products of the wood are dissolved and removed by the liquor, and then placing the liquor in a container to permit oxidation, aldehydation and esterification of the liquor.

v4. In a method of treating oak wood to produce a prolific cryptogamic growth which promotes oxidation, aldehydation and esterification during the aging of spiritous liquors, the'steps which consist in reducing the wood to a comminuted form, and moistening the comminuted wood with a solution containing an emulsin cornplex and ether which will produce esterification.

5. In amethod of treating oak wood to produce a prolific cryptogamic growth which promotes oxidation, aldehydation and esterification during the aging of spiritous liquors, the steps which consist in reducing the wood to -a comminuted form, and moistening the comminuted wood with a solution containing ether and an emulsin complex derived from the genus Prunus.

6. In a method of treating oak wood to pro-- duce a prolific cryptogamic growth. which promotes oxidation, aldehydation and esterification during the aging of spiritous-liquors, the steps whichconsist in reducing the wood to a comminuted form, and hydrolizing the tannin and tanno compounds contained in the comminuted wood by subjecting the wood to the action of a solution containing ether and an emulsin com-- plexderived from a source other than the wood.

- ERNST T. KREBS.

ERNST T. KREBS, JR. 

